English

Lifting banal representations of classical groups

Representation Theory 2026-04-10 v1 Number Theory

Abstract

Let G\mathrm{G} be a symplectic or a split orthogonal group over a local non-archimedean field F\mathrm{F}. A prime \ell is called banal with respect to G\mathrm{G} if it does not divide the cardinality of the kk-points of G\mathrm{G}, where kk is the residue field of F\mathrm{F}. In this paper we show that for every banal prime \ell, any smooth irreducible F\overline{\mathbb{F}}_\ell-representation of G(F)\mathrm{G}(\mathrm{F}) admits a lift to Q\overline{\mathbb{Q}}_\ell. We also state similar results for more general classical groups of symplectic, orthogonal or unitary type. As an application we prove Howe-duality in the strongly banal case for symplectic-orthogonal or unitary dual pairs.

Keywords

Cite

@article{arxiv.2604.07516,
  title  = {Lifting banal representations of classical groups},
  author = {Johannes Droschl},
  journal= {arXiv preprint arXiv:2604.07516},
  year   = {2026}
}
R2 v1 2026-07-01T11:59:59.569Z